I started with the back of the jacket, and I made an upside down cross. (Historical note: The upside down cross, while adopted by Satanists, anarchists, and rebels, is in fact a symbol begun by Peter the Apostle when he asked to be crucified upside down because he felt he was not worthy to be crucified right side up as Jesus was. I decided to look it up beforehand because my mom's wigging out over the supposed Satanic symbolism.)

I basically just took the pointy parts of the back of the studs, stuck them through my jacket, and bent them shut with my fingers. a tutorial can be found here.

For the spikes on the shoulders, it was a little harder because it's a screw mechanism, so I had a screwdriver handy. I poked holes for the screws with the pointy part of the big gold spike, and then proceeded to insert and screw (keep your mind out the gutter, guys). I alternated between the teeny tree spikes and the huge cone ones. This is the final product!